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Finding the Fourth Proportional to 816.78, 1,222.20 and 508.80

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Solution

The fourth proportional to 816.78, 1,222.20 and 508.80 is: 761.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.78 : 1,222.20 = 508.80 : x
  2. Step 2: Convert to fraction form
    816.78/1,222.20 = 508.80/x
  3. Step 3: Cross multiply
    816.78x = 1,222.20 × 508.80
  4. Step 4: Simplify right side
    816.78x = 621,855.36
  5. Step 5: Solve for x
    x = 621,855.36/816.78
  6. Step 6: Final answer
    x = 761.35

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.